1. Field of the Invention
This invention relates to a general-purpose internal combustion engine, particularly to a general-purpose internal combustion engine equipped with an actuator for driving a throttle valve.
2. Description of the Related Art
Conventionally, electronically-controlled throttle apparatuses (electronically-controlled governors) utilizing an actuator such as a stepper motor to open and close a throttle valve for accurately controlling engine speed have been applied to general-purpose internal combustion engines used as prime movers in generators, agricultural machines and various other equipment.
In recent years, there is proposed a technique for improving engine starting performance by employing an automatic choke apparatus that uses an actuator to open and close a choke valve of a general-purpose engine so as to close the choke valve at cold start or the like for producing a rich air-fuel mixture. When the automatic choke apparatus is applied to the above-mentioned engine, in addition to the actuator for the throttle valve, the engine will need another actuator for the choke valve, as taught, for example, by Japanese Laid-Open Patent Application No. 2007-23838 (paragraphs 0022, 0036, FIG. 2, etc.).
However, the additional installation of an actuator for the choke valve as set forth in the prior art requires an extra space for the installment of the actuator and the like, disadvantageously increasing the size of the entire engine.